Epoxy esters of polycarboxylic acids



Patented Feb. 25, 1964:

moiety connected by a methylene group as illustrated by 3,122,553 the foilowing structure EFGXZ ESTERfi F PQLYCARBQXYLIC AfiDS 1 1 501131 W. Lynn, Qhariesten, Richard L. Roberts, Mitten,

and Smuei W. Tinsley, South harleston, W. V2. as- ROZCC' CGOER signers to Union fiat-bide Corporation, a corporation of New York /CHR1 No Drawing. Filed May 22, 19%, Ser. No. 31453 2 0HCGOR 5 Claims. (ct. ass-34s This invention relates to epoxy esters of polycarboxylic whfrein g andflRl an? as defified hereinbeforeacids having utility as plasticizers and stabilizers for vinyl i i l Preferred P Y esters are In Whlch halide resins, and as monomers for the preparation of R1 ls'memyli f P FE'YL P PYL bu'iyl, lsobulyl, and valuable resins. In a particular aspect, this invention is the f and R 111631311, Y YL y 3 P PYL directed to epoxy aliphatic esters of 1,2,4-butanetricar- E PEL buiyl, y i lsfibutyi, yy amyl, boxyfic acids, 3-pe tenyl, 2-hexenyl, hexyl, heptyl, octyl, 2-octenyl, 2-

This invention provides aliphatic triesters of 1,2,4-bug Zfithybzhexenyl: 119W}, 3 z'decfinyb tanetricarboxylic acids having at least one oXirane-con- Y L Wiadficyl, 9-octadficenyl, and P 3 taining aliphatic alcohol radical. By the term oxirane P s radicals Such as P YP PYL J- P Y YL is meant the 2-chioro-3,4-epoxybutyl, 2,3-epoxy 2 ethylhexyl, 3,4-

20 epoXy-l-butenyl, the epoxidized derivatives of the foregoing allzenyl radicals wherein the double bond is converted into an oxirane group, and other similar aliphatic radicals. Typical preferred epoxy aliphatic esters include structure; and by the terms epoxy aliphatic radical,

epoxyalkyl radical and epoxyalkenyl radical, are

meant aliphatic, alkyl and alkenyl radicals, respectively, containing at least one of said oxirane structures.

A preferred class of epoxy esters of this invention are those cor snondin to the eneral formula g D 2,3-epoxypropyl bis(oxo decyl) 1,2,4-

cyclopentanetricarboxylate; ROzCCOH-C 02R 2,3-epoxy-2-ethylhexyl bis(2-ethyl-2-hexenyl) 2 1 1 ,2,3 ,4-tetrafluoro-1,2,4-butanetricarboxylate;

bis (2,3 -ep oxybutyl) vinyl 2-butyl-1,2,4-

tris (2,3-epoxypropyl) 1,2,4-butanetricarboxylate;

tris(9,10-epoxyoctadecyl) 1,2,4-butanetricarboxylate;

tris(2,3-epox -2-ethylhexyl) l,2,4-butanetricarboxylate; 2,3-epoxypropyl diallyl 1-chloro-1,2,4-

butanetricarboxylate;

I V butanetricarboxylate; R R1 2,3-epoxy-2-ethylhexyl ethyl Z-ethylhexyl 1,2,4- wherein R is a member selected from the group consistbutallfiificaflfioXjla'ie; and the likeing of hydrogen and lower alkyl radicals comalrimg Th. enoxy alinhatic esters of this invention are readily mean one and about four Carbon atoms; Wheran R pre ared by the epoxidation of the corresnonding olefinic n nun" v a i an i l ff f at least One 1S f EPOXY i 49 esters. Preferred epoxzdatron methods involve the use Phallg f total numbe? of camcfn atoms 13 or" peracetic acid or acetaldehyde monoperacetate as the said R radicals is between five and about sixty carbon epoxidizing agmt Epoxidation employing acetaledehyde monoperacetate Famculafly Prefermd P Y esters csnesllondmg to proceeds as illustrated in the following equation with th above general formula are these in Which the tris(2-ethyl-2-hexenyl) 1,2,4-butanetricarboxylate as the phatic radical R is a member selected from the group orefinic starting material:

C02- OHHO CzH5 GHOH2CO +3OH3OH o-om oH@ oH2)=oH=ooH: a

CH2CH2CO2 OO C2115 ([102- CHQ(CH2)2C\E\I/GCHZ CHCH2OO2 +3CHaCO2H+3CHaCHO 3 OHQCHQO 02-- consisting of alkyl radicals containing between one and Epoxidation employing peracetic acid proceeds as fllus- E g t n CP atoms, fllkeilyl Iadlcfils al ng trated in the following equation with tris(9-octadecenyl) tw en two nd e ghteen carbon atoms, and epoxyalkyl 1,2, l-butanetricarboxylate as the olefinic starting material:

and epoxyalkenyl radi als containing between two and eight en carbon atoms, and at least one R is an epoxy- 1- alkyl radical or epoxyalkenyl radical, and the total nurn- 0 [CSH1TCH:OH(CH2)7OH2 13 CHCHNOP CHKCWHQ er of carbon atoms in said R radicals is between nine 013201320 O2 and forty-eight carbon atoms. These esters can contain [CgH17GH=-OH(CH2)7 2 ]2 CO2- halogen atoms are Eurther characterized as being free 0 CHCHzCHP or acetylenic unsaturatron. g

The above general formula is meant to include tri- 55 CBH11CH- CH(OH1)1CH2 CHICHICQP esters of 1,2,4-butanetricmboxylic acids which have the The suitable olefinic ester starting material which are number one and number four carbon atoms of the acid epoxidized to produce the novel epoxy esters of this invention are readily prepared by conventional esterification and transesterifieation methods from appropriate aliphatic alcohols and l,2,4-butanetricarboxylic acids. in one direct esterification method, an alcohol such as 2- ethyl-Z-hexen-l-ol is reacted with a polycarboxylic acid such as l,2,4-butanetricarboxylic acid in the presence of a strong acid catalyst such as paratoluenesulfonic acid with the continuous removal of Water as an azeotrope with an entraining agent such as benzene or toluene. In another direct esterification method, the alcohol is reacted With the tricarboxylic acid in the form of its acid halide derivative in the presence or" an acid-binding substance such as pyridine. In the transesterification method, an alcohol such as 9-octadecen-l-ol is reacted with an ester derivative such as triethyl l,2,4-butanetricarboxylate in the presence of a catalyst such as tetraalkyl titanate with the continuous removal of the replaced alcohol (e.g., ethanol) as a solitary distillation component or as an azeotrope With toluene or a similar entraining agent. The quantities of acid and alcohol reacted may be varied over broad molar ratios but it is usually preferred to employ either stoichiometric quantities of acid and alcohol or a small molar excess of alcohol. For example, for the preparation of an ester which has three similar alcohol moieties, the unsaturated aliphatic alcohol is reacted with the 1,2,4-butanetricarboxylic acid in the ratio of three moles of alcohol for each mole of tricarboxylic acid. In the case of an ester which has dissimilar alcohol moieties, the respective alcohols are employed in the appropriate ratios. For example, when three difi'erent alcohols are to be reacted With a 1,2,4-butanetricarboxylic acid, a ratio of one mole of each of the alcohols is employed for each mole of tricarboxylic acid. The alcohols can be reacted individually with the tricarboxylic acid, or the alcohols can be reacted simultaneously as a single mixture with the tricarboxylic acid. In either case, an equilibrium reaction product is formed.

The epoxy aliphatic esters of this invention can also be prepared directly by the interaction of suitable epoxy aliphatic alcohols with l,2,4-butanetricarboxylic acids. This method is not preferred because of the various side reactions Which can occur.

The class of l,2,4-butanetricarboxylic acids useful for the production of the novel esters of this invention are available by several preparative routes which are reported in the chemical literature. For example, 1,2,4-butanetricarboxylic acid can be prepared by the Michael condensation of rnethylene-succinic acid ester with malonic ester, or by the condensation of acrylonitrile, with 1,1,2-ethanetricarboxylic acid. A preferred anethod of preparing 1,2,4-butanetricarboxylic acids is by the nitric acid oxidation of cyclohexene derivatives corresponding to the formulas wherein X is a carboxyl group or a group convertible to a carboxyl group such as cyano, keto and amido groups, and R is hydrogen or a lower alkyl group containing between one and four carbon atoms. The appropriate cyclohexene derivatives, in turn, are prepared by the Diels- Alder reaction of butadiene and other compounds of the conjugated diene series with mono-olefinic dienophiles having the double bond in a position vinyl to a carboxyl group or a group convertible to a carboxyl group. Suitable dienophiles are illustrated by acrylic acid, crotonic acid, methacrylic acid, acrylonitrile, alkyl acrylate, alkyl methacrylate, acry-larnide, N,N-dia-lkyl-crotonamide, and the like. Among the suitable conjugated dienes are ind eluded cyclopentadiene, butadiene, piperylene, isoprene, and the like.

A mentioned above, the epoxy aliphatic esters of this invention are useful as plasticizers and as heat and light stabilizers for vinyl halide resins and as monomers for the preparation of valuable resins. For example, tris(9, lO-epoxystearyl) l,2,4-butanetricarboxylate has good low temperature performance a ia plasticizer for poly(vinyl chloride), and tris-(2,3-epoxy-2-ethylhexyl) 1,2,4-butanetricarboxylate is superior to Paraplex G-62 (epoxidized soybean oil) as a light stabilizer for poly(vinyl chloride).

The epoxy aliphatic esters are susceptible to polymerization by way of the epoxy groups. The polymerization can proceed by epoxy-epoxy interaction, or by interaction of epoxy groups with other functional groups such as anhydride and active hydrogen groups. Compounds containing active hydrogen groups are illustrated by polycarboxylic acids and polyhydric alcohols and phenols. The epoxy aliphatic esters containing olefinic unsaturation, e.g., bis(2,3-epoxypropyl) vinyl l-butyl-l,2,4-butauetricarboxylate, have the additional feature of being polyrnerizable both through the epoxy groups and through the olefinic groups. These two dissimilar groups react to form polymers by entirely dififerent reaction mechanisms. The unsaturated epoxy ester can be subjected to conditions whereby polymerization occurs through one kind of group to the exclusion of polymerization through the other kind of group. The resulting polymer then can be further polymerized under the proper conditions through the unaffected second kind of group so that a more rigid, tougher resin is formed. For example, an unsaturated epoxy ester of this invention can be copolyrnerized with a vinyl monomer such as vinyl chloride to form a copolyrner containing unreacted epoxide groups which could then be cross-linked by treatment with acid or base to induce reaction of the available epoxide groups. Or, on the other hand, an ester of this invention can be copolymerized with a monomer such as ethylene oxide or ethylenediamine to form a copolymer which contains double bonds capable of cross-linking by treatment with a peroxide or by heat at an elevated temperature. The dissimilarity of the polymer-forming epoxy and olefin groups enables control over polymer formation so as to produce polymers having a great variety of properties.

The following examples will serve to illustrate specific embodiments of the invention.

Example 1 A solution (915 grams) of 21.5 percent peracetic acid in ethyl acetate was added dropwise to tr-is(2-ethyl-2- hexenyl) 1,2,4-butanetricarboxylate (309 grams) at a temperature of C. over a period of ninety minutes. After an additional three hours at 50 0, analysis of the mixture for peracetic acid indicated that the reaction was complete. The reaction mixture was then fed drop wise to an equal volume of ethylbenzene which was refluxing in a distillation apparatus at a pressure of 25 to 30 millimeters of mercury. Ethyl acetate, acetic acid and excess peracetic acid together with ethylbenzene were distilled ofi overhead. The concentrated reaction mixture consisted of tris(2,3-epoxy-2-ethylhexyl) 1,2,4- butanetricarboxylate having the following properties: 6.75 percent oxirane oxygen (80 percent purity), 0.31 percent acid (calculated as acetic acid), iodine value (Wijs method) 1.09, and color less than 1 Gardner.

Example 2 A solution (1980 grams) of 26.1 percent peracetic acid in ethyl acetate was fed dropwise to triallyl 1,2,4-butanetricarboxylate (527 grams) at a temperature of C. to C. over a period of five hours. After an additional six and one-half hours at 60 C. to C. the mixture was stripped of volatiles by passing through a steam heated evaporator. Triglycidyl 1,2,4-butanetricarboxylate (616 grams) was recovered as a residue product which contained 7.6 percent oxirane oxygen by epoxide analysis.

Example 3 A solution (392 grams) of 27.9 percent peracetic acid in ethyl acetate was added dropwise to trioleyl 1,2,4- butanetricarboxylate (380 grams) at a temperature of 45 C. to 50 C. over a period of fifty minutes. After five hours of additional heating at 45 C. to 50 C., all volatile materials were removed under vacuum distillation. Tris(9,10-epoxyoctadecyl) 1,2,4-butanetricarboxylate (394 grams) was obtained as a residue product which contained 3.89 percent oxirane oxygen by epoxide analysis.

Examples 7 through 12 triglycidyl 1,2,4-butanetricaracidic and basic hardeners in in the following table. Gel

One-gram portions of boxylate were mixed with the proportions indicated Example 4 5 times were observed and the resulting gels were post- A solution (267 grams) of 27.6 percent peracetic acid cured as indicated.

Ex.No. Hardener Grams Ratio 3 Gel Time, Cure, Hours, C. Resin Descrip- Minutes, 0. tion 7 Diethylenetriamine 0.11 1.0 40,26 24, 26; 5.5, 80; 2.5, Brown, tough,

120; 6, 160. Barcol, 0. 8 p,p-\1ethylenedianiline 0.25 1.0 30, 120 7, 120; 6, 160 Arlgrbenltough,

area 37. 9 Phthalicanhydride 0.55 1.5 15, 120 6, 120; 6, 160 Yelowgough,

area 33. 10 Potassimn hydroxide 0.4% after 12, 120-.. 18, 26; 5.5, 80; 2.5, Brown, tough,

120; 6, 160. Barcol, 0. 11 Sulfuric acid 0.4% after 60, 80".. 19, 26; 5.5, 80; 2.5, Brown, Bareol,

120; G, 160. 20. 12 BFa-piperidine 0.05 5.0% 50,120 3,120;6,1.60 Brown, tough,

Barcol, 0.

a Ratio of amino-hydrogen or carboxyl groups per epoxy group. b Added as a 17.3 percent solution in water. Added as a 15 percent solution in water.

in ethyl acetate was added dropwise to triallyl 1,2,4- butanetricarboxylate (290 grams) at a temperature of 50 C. over a period of one hundred five minutes. After three hours of additional heating at 50 C., the temperature was raised to 60 C. and maintained for three and one-half hours, at which time analysis indicated the reaction to be substantially complete. As in Example 1, volatile materials were distilled with ethylbenzene from the reaction mixture. There was obtained 146 grams of product, boiling point 168 C. at a pressure of 0.06 millimeter of mercury, which had as a major component 2,3-epoxypropyl diallyl 1,2,4-butanetricarboxylate, and there was obtained 45 grams of product, boiling point 186 C. at a pressure of 0.14 millimeter of mercury, which contained as a major component di(2,3-epoxypropyl) allyl 1,2,4-butanetricarboxylate. The pyridine hydrochloride method was employed to determine the epoxide content of the products.

Example 5 A solution of ethyl acetate containing -30 percent by weight of peracetic acid (approximately 3.6 moles) is added dropwise to trioleyl 1,2,4cyclopentanetricarboxylate (approximately 1.0 mole) at a temperature of 45 C. to 50 C. over a period of one hour. After five hours of additional heating at 45 C. to 50 C., all volatile materials are removed by feeding the mixture dropwise to an equal volume of ethylbenzene which is refluxing in a distillation apparatus at a pressure of to millimeters of mercury. Ethyl acetate, acetic acid and excess peracetic acid, together with ethyl benzene are distilled off overhead. The concentrated reaction product consists of tr-is(9,IO-epoxyoctadecyl) 1,2,4-cycl0pentanetricarboxylate.

Example 6 A solution of ethyl acetate containing 20-30 percent by Weight of peracetic acid (approximately 4.5 moles) is added dropwise to tris(2-ethyl-2-hexenyl) 1,2,4-cyclopentanetricarboxylate (approximately 1.0 mole) at a 1 Pyridine hydrochloride method,

What is claimed is: 1. An epoxy ester of the formula:

wherein R is a member selected from the group consisting of hydrogen and lower alkyl containing between one and four carbon atoms; R is a radical selected from the group consisting of alkyl of from one to eighteen carbon atoms; aikenyl, epoxyallcyl and epoxyalkenyl of from two to eighteen carbon atoms, and at least one of the radicals represented by R is an epoxy radical as aforesaid, and the total number of carbon atoms in said R radical is between five and about sixty carbon atoms.

2. T ris(9,10-epoxyoctadeeyl) 1,2,4-eyclopentanetricarboxylate.

3. Tris 2,3-epoxy-2-ethylhexyl) carboxylate.

4. 2,3-epoxypropyl diallyl 1,2,4-butanetricarboxylate.

1,2,4-cyclopentanetri- 5. Bis(2,3-epoxypropyl) allyl 1,2,4-butanetricarboxylate.

References Cited in the file of this patent UNITED STATES PATENTS 2,476,922 Shokal et al July 19, 1949 2,781,333 Updegraff Feb. 12, 1957 2,783,250 Payne et al Feb. 26, 1957 2,890,210 Phillips et a1 June 9, 1959 2,895,947 Shokal et al July 21, 1959 2,935,492 Newey May 3, 1960 3,057,880 Lynn et al. Oct. 9, 1962 3,062,871 Lynn et a1 Nov. 6, 1962 FOREIGN PATENTS 559,078 Canada June 17, 1958 

1. AN EPOXY ESTER OF THE FORMULA: 